Energy minimization calculations and quantum mechanical calculations on compounds of biological and pharmacological interest continue to give insights into and explanations of their modes of behavior, resulting in clues to their pharmacophores. The inhibition of the enzyme aldose reductase by a wide variety of compounds continues under investigation by QSAR techniques, as well as by energy minimization computations, quantum mechanics and stereochemical considerations. The pertinent factors have now been shown to include also bulk terms. Energy minimization and quantum calculations have been carried out on the various conformations and colchicine and isocolchicine to correlate binding properties with the energies and structure of their conformations. Various compounds showing promise against the AIDS virus are being systematically investigated to obtain structural and electronic properties which may help elucidate the mechanism of their action, and thus lead to improved forms. Energetic, structural and electronic properties of AZT have been obtained, as well as rotational barriers due to the base group. The binding of analogs of colchicine has been investigated further by QSAR methods. In addition to partition coefficients, binding efficiency depends on free energy and molecular volumes.